In the wake of yet another negative trial, Pfizer Inc. has discontinued research on bapineuzumab, a monoclonal antibody designed to target amyloid beta plaques in the brains of patients with Alzheimer’s disease.
The phase III trial failed to meet any of its cognitive or functional endpoints in 1,100 patients who were negative for the high-risk apolipoprotein E4 allele (apo E4). These new results, combined with disappointing outcomes in a separate study of apo E4 carriers, were the knockout punch for bapineuzumab.
Dr. Steven J. Romano, head of the Medicines Development Group at Pfizer’s Global Primary Care Business Unit, said in a written statement that the company was disappointed in the clinical outcomes.
"We are ... saddened by the lost opportunity to provide a meaningful advance for patients afflicted with mild to moderate Alzheimer’s disease and their caregivers."
In July, Pfizer reported negative results in a phase 3 study of the drug’s effect on 1,300 apo E4 carriers with Alzheimer’s disease. The primary endpoints of both studies were changes in the Alzheimer’s Disease Assessment Scale-Cognitive subscale (ADAS-Cog), and the Disability Assessment for Dementia (DAD).
There were no new signs of any safety problems in either study. Adverse events, which included pneumonia, syncope, hip fractures, and convulsions, were significantly more common in the active group, compared with the placebo group. Some patients also experienced cerebral vasogenic edema and microhemorrhages.
In the wake of these negative results, Pfizer will also discontinue two other phase III studies in patients with mild to moderate Alzheimer’s, including two follow-up extension studies.
Dr. Romano said that subgroup analyses on the studies will continue. "These data, and the subgroup and biomarker analyses underway, will further inform our understanding of this complex disease and advance research in this field."